Lever unlocking means in toggle action clamping devices



July 14, 1959 w, LAMPE 2,894,547

LEVER UNLOCKING MEANS IN TOGGLE ACTION CLAMPING DEVICES Filed May 1, 1957 v INVENTOR. fr'v'ejrz'cvz 14 J4777pe 22? BY 23E-575LM%*% ZVMECPQ:

United States Patent LEVER UNLOCKING MEANS IN TOGGLE ACTION CLAMPING DEVICES Friedrich W. Lampe, Detroit, Mich, assignor to Lapeer Manufacturing Company, Lapeer, Mich, a corporation of Michigan Application May 1, 1957, Serial No. 656,321

2 Claims. (Cl. 144302) This invention relates to new and useful improvements in manually operated toggle action clamping devices and more particularly to improved lever unlocking means in devices of this type.

Lever unlocking means in toggle action clamping devices have been proposed for increasing the ease with which the handles can be separated for releasing the jaws from closed lock position. That is, with toggle action clamping devices having lever unlocking means, an operator can separate the handles with less force by reason of the lever. However such lever unlocking means for toggle clamping devices that have been heretofore proposed are deficient in that they provide no control over the swinging movement of the handles in opening. In other words the handles are free to spring open and swing to maximum separation which is beyond the hand span of the user so that two hands are required to reapply the device.

An important object of the present invention is to provide improved lever unlocking means in a toggle action clamping device which is so constructed in relation to the toggle linkage for the device and to the pair of handles for the same that the swinging movement of the latter in opening the jaws from closed lock position is controlled in that one handle always remains connected to the lever and the distance which it can swing open relative to the other handle is determined by the user and in that the lever and the other handle always remain within the hand span of the user.

Another important object of the invention is to provide unlocking means in toggle action clamping devices which includes means which pivotally mount the lever on one of the handles so that the fulcrum of the lever reacts on the other handle and the reaction of the lever is applied tothe said one handle so that the lever and either handle may be squeezed and relatively moved together whereupon unlocking of the jaws and separation of the handles into open position occurs and whereby the swinging movement of the pair of handles occurring in one way of opening is controlled as indicated and wherein the construction of said lever unlocking means permits adjustment of the jaws to any desired position and their reapplication by only one hand of the operator relatively moving the said other handle and the lever leaving his other hand free to accomplish other results.

The above and related' objects will appear more fully during the course of the following description taken in conjunction with the accompanying drawings.

In the drawings:

Fig. 1 is a front elevational view of a typical toggle pliers in combination with the improved unlocking means of the present invention, the position shown being closed lock position;

Fig. 2 is an enlarged perspective view of the lever shown in Fig. 1 looking at the inside of the same;

Fig. 3 is a fragmentary front elevational view of the handle-half of the pliers showing the lever unlocking 2,894,547 Patented July 14, 1959 ice means and handles in an intermediate position when the pliers are opened from one side;

Fig. 4 is a view similar to Fig. 3 showing the parts in a further open position when the pliers are opened from the same side as in Fig. 3; and

Fig. 5 is a view similar to Figs. 3 and 4 showing the handle-half of the pliers in wide open position when they have been inverted and opened from the opposite side from that in the previous figures.

Referring now to the drawings in greater detail there is shown therein the lever unlocking means of the present invention in combination with a typical toggle pliers, the latter comprising a pair of jaws 7 and 9 which are connected together by a common pivot connection indicated at 11. At the free end of the jaws or throat of the pliers, an anvil 13 is secured on the inside of the jaw 7 and the jaw 9 is provided with an adjusting spindle 15 which it threadably carries. The spindle 15 may be rotated so as to move transversely with respect to the jaw 9 to adjust the gap between its lower end and the anvil 13. Such adjustment is to accommodate different workpiece sizes and for a given workpiece size to vary the applied load. When the gap between the lower end of the spindle 15 and the anvil 13 is decreased for a given workpiece size the clamping force is proportionately greater. On the upper end of the spindle 15 a fastener 17 is threadably received for bearing against the outside of the jaw 9 to retain the spindle in any selected position.

A pair of handles 21 and 23 are connected together by a common pivot connection 25 and individually to the pair of jaws each by one of a pair of pivot connections indicated at 27 and 29 for the handles 21 and 23 respectively. The free ends of the jaws are brought together by separation of their pivoted ends at the pivot connections 27 and 29, the jaws commonly fulcruming on their common pivot connection 11. Conversely the jaws are opened by relative movement of their pivoted ends toward each other. The separation or bringing together of the pair of pivot connections 27 and 29 occurs by movement of the common pivot connection 25 for the handles 21 and 23 between the pivot connections 27 and 29. Thus when the handles are squeezed together their common pivot connection 25 is caused to move inwardly toward the throat of the pliers thus separating the pivoted ends of the pair of jaws and actuating their free ends together so that the spindle 15 moves closer to the anvil 13.

When it is desired to clamp two objects together such as those shown by way of illustration and indicated at 31 and 33 in Fig. 1, the same are positioned between the anvil 13 and the spindle 15. Further movement of the spindle 15 toward the anvil 13 is resisted by the interposed work-pieces so that it then becomes necessary to squeeze the handles 21 and 23 together with greater force which causes their common pivot connection 25 to move into dead center condition with respect to the pair of pivot connections 27 and 29, i.e. with the center of the pivot connection 25 in line with the centers of the pivot connections 27 and 29. In final movement of the common pivot connection 25 into dead center condition the pivoted ends of the pair of jaws separate but their free ends are held immobile by the pair of work-pieces that are to be clamped so that the jaws 7 and 9 are flexed under load and a certain amount of force, depending upon the setting of the spindle 15, is stored in the jaws when they are thus clamped under load. In this position since the common pivot connection 25 is in dead center condition with relation to the pair of pivot connections 27 and 29, no amount of outward force applied to the pair of jaws 7 and 9 short of breakage of parts will cause them to separate. The handles however may be separated to actuate the pair of jaws out of closed lock position and without any lever unlocking means it may require two hands to pull the pair of handles 21 and 23 apart. The construction and operation of the toggle action pliers per so as thus described is entirely conventional.

When the lever unlocking means of the present invention is positioned between the pair of handles, the jaws may be separated by an operator using only one hand and in so doing he may grasp the lever and either one of the handles (the unlocking action differing depending upon which handle is grasped) and squeeze the two together whereupon the handles will separate and release the jaws from closed lock position. The term closed lock position as used throughout the specification and in the appended claims is intended to refer to that position described above for the jaws and when they are under load so that there is always an amount of flexure in the jaws resisting initial opening. In one way in which the handles may be separated there is provided by virtue of the unlocking means to be described in detail, a unique and novel control over the swinging movement of the handles in opening. While such control is provided in only one way of opening the pliers this is very desirable and all that is necessary because the pliers are normally used in only one way which is the position shown in Fig. 1. Therein it will be noted that the anvil jaw 7, i.e. the one provided with the anvil 13 is the lower jaw and the spindle jaw 9 is the upper jaw. By far the greatest majority of the occasions of use of the pliers is with the anvil jaw positioned below the work and with the spindle jaw being brought to bear thereon from above.

Referring now in detail to the applicants unlocking means, the same comprises a lever, generally designated 35, which is pivotally connected to the pliers so that it extends in the same general direction as the handles and is disposed therebetween. The lever is permanently associated with the pliers due to the pivotal connecting means therefor and is thus prevented from moving away from the handles in the direction in which it extends from any reaction to its lever action. The means for connecting the lever 35 to the pliers pivotally mounts the former on one of the handles which is the handle 21 in the instance shown and includes an integral abutment 37 which protrudes laterally from the inside surface of the handle 21 toward the handle 23. The abutment 37 is provided with a suitable aperture through which a rivet or pivot pin as at 39 may extend. The pivot pin 39 also extends through aligned apertures 41 provided each in one of a pair of spaced side plates 43 formed on the upper end of the lever 35 as best shown in the perspective view of Fig. 2. The ends of the pin 39 may be peened over or otherwise enlarged relative to the apertures 41 to provide a pivot connection for the lever hereinafter designated point A. The particular construction shown for the lever 35 includes besides the side plates 43 an integral back plate 45 which joins the side plates along their top edges as viewed in Fig. l and, as will be noted, these taper upwardly with respect to the handle 21 and outwardly as viewed in this figure. is positioned to conform to the inside surface of the handle 23 which it bears against in the closed lock position of the pliers. At the lower right hand end of the side plates as viewed in Fig. 1, they are joined together into a handle extension 47 which projects outwardly nearly as far as the handles of the pliers. The handle extension 47 is the point of action for the lever to which force is applied and is constructed to provide a smooth surface for gripping on both of its sides. It should also be noted from Fig. 1 that the apertures 41 being part of the lever pivot connection are located in the side plates 43 adjacent their lower edges just to the right of the junction of the latter with the left hand or inner edges of the side plates. The said inner edges of the side plates 43 taper upwardly and inwardly as viewed in Fig. 1 to where they meet the inner edge of the back plate 45. The

Thus the rear plate 45 back plate 45 is thus spaced at all times from the handle 21 and in the closed lock position of the pliers'the outer end of the back plate is located above and to the right of point A while the inner end of the back plate is located to the left of point A and above the same but vertically between the outer end of the back plate and point A.

The outer end of the plate 45 is hereinafter designated point B and acts as a fulcrum for the lever against the handle 23 in the preferred way of opening the pliers as will later appear more fully. The lever pivot connection or point A applies the reaction of the lever to the handle 21 in the said preferred way of opening and in the other way of opening the handles acts as a fulcrum against the handle 21 as also will apear hereinafter. The inner end of the plate 45 in the said other way of opening applies the reaction of the lever against the handle 23 and will be hereinafter designated point C. The spacing of this point from the inside surface of the handle 21 permits the handle extension 47 of the lever to be moved toward the handle 23 to position the back plate 45 at a decided angle to the horizontal such as shown in Fig. 3, to which reference will be made shortly, so that the point B may be moved closer to the handle 23 and the point C closer to the handle 21 than that shown for these points in Fig. 1.

In operation of the lever unlocking means in the usual way of opening the pliers, the handle 23 and the lever 35 by way of its handle extension 47 are grippedand squeezed together in the hand of the operator. The point B acts as a fulcrum for the lever against the handle 23 in this way of opening the pliers and the lever pivot connection or point A applies the reaction of the lever to the handle 21. Upon squeezing the lever and the handle 23 together the lever pivots on its fulcrum point B and snaps into an intermediate open position as shown in Fig. 3, the lever pivot connection or point A having forced the handle 21 away from the handle 23 to break the dead center condition for the common pivot connection 25. In this respect it will be noted from Fig. 3 that the pivot connection 25 has moved from the rearward portion of the jaw 7 and this should be compared to the relative position for these parts shown in Fig. l. A small but certain amount of force is required to retain the lever in the position shown in Fig. 3, this force counteracting the tendency of the jaws which are still closed in this position to throw the handles apart due to the flexure within the jaws. Upon release of the force holding the lever and the handle 23 in intermediate open position, but while they are still retained together within the grip of the operator, the handles move apart to a further open position as shown in Fig. 4 due to the energy stored in the jaws under load. In this position the jaws are separated an amount corresponding to the separation of the handles but the handle 23 and the lever 35 are still retained within the grip of the user as mentioned and as shown in Fig. 4 and it will be noted that the handle 21 always remains connected to the lever 35 so that the distance which it moves away from the handle 23 can be controlled as desired by the user.

Thus in the swinging movement of the handles into open position they are always under the control of the user and since the handle 21 remains connected to the lever 35, the jaws may be closed as desired by pulling the lever 35 toward the handle 23. Similarly the jaws may be opened wider 'by the operator with the back of his fingers which are retained about the lever 35 between the latter and the handle 21. Thus with only one hand by means of the handle 23 and the lever 35 an operator is able to adjust the separation of the jaws similarly as he could do with the actual handles of the pliers if they did not swing open beyond his hand span.

By this manner of opening the plier jaws, the pliers have even a greater range of use in industrial applications because the pliers can be quickly removed with one hand and can just as quickly be reapplied, also with one hand. By means of the lever unlocking means of the present invention the handle 21 can be drawn inwardly toward the handle 23 so that in the final application of the clamping force, the pair of handles 21 and 23 are within the hand span of the user who can then squeeze them together to apply the pliers to the objects to be clamped. It is oftentimes required such as in molding operations to alternately clamp and remove the pliers on a production basis as, for example, in clamping flanges of mating die parts wherein a plurality of such pliers are employed around the periphery of the die. Tospeed production each operator may remove a pair of pliers simultaneously one with each hand and a plurality of such pairs in succession and later reapply them in the same manner.

Not only are the above advantages provided in opening the pliers in the preferred way as described but also the lever unlocking means of the present invention is double acting in that the pliers can also be opened by squeezing together the lever and the handle 21 in the event that, through inadvertenoe, the pliers are applied in an inverted position from that shown in Fig. 1 as in Fig. 5. In such instance the lever pivot connection or point A functions as a fulcrum for the lever against the handle 21 and the point C applies the reaction of the lever against the handle 23. In this other way of opening the pliers the handle 21 and the handle extension 47 of the lever are grasped by an operator and the two are squeezed together as shown in Fig. 5. The lever rocks on its pivot connection or point A and urges the point C against the handle 23 to move the latter away from the handle 21 and to cause the common pivot connection 25 to move from its dead center position and immediately the handles are swung open to the position shown in Fig. 5 by the flexure imparted to the jaws 7 and 9 when they are under load. The jaws though not shown are separated an amount corresponding to the separation of the handles. There is no intermediate position for this way of opening the pliers and there is no control over the handle 23 in its swinging movement relative to the handle 21.

It will thus be seen that there has been provided by the present invention lever unlocking means in toggle action clamping devices in which the objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. It will be apparent that the invention is susceptible to variation, modification and change without departing from the spirit thereof or from the scope of the appended claims.

What is claimed is:

1. In a manually operated toggle action clamping device having a pair of clamping jaws, toggle linkage means connecting the jaws together, and a pair of handles connected to said linkage means for movement toward and away from each other to move said jaws toward and away from each other, respectively; an unlocking lever pivotally mounted intermediate the ends thereof on one of said handles so that said lever is between said handles, said lever having a first portion engageable with the other one of said handles for moving said handles apart in response to swinging movement of the lever in one direction, said lever having a second portion engageable with said linkage means in an open position of said jaws for moving said jaws toward closed positions on swinging of said lever in said one direction.

2. In a manually operated toggle action clamping de vice having a pair of clamping jaws, toggle linkage means connecting the jaws together, and a pair of handles connected to said linkage means for movement toward and away from each other to move said jaws toward and away from each other, respectively; an unlocking lever pivotally mounted intermediate the ends thereof on one of said handles so that said lever is between said handles, said lever having a first portion engageable with the other one of said handles for moving said handles apart in response to swinging movement of the lever in one direction, said lever having a second portion engageable with the other one of said handles for moving said handles apart in response to swinging movement of the lever in an opposite direction, said second portion being engage able with said linkage means in an open position of said jaws so as to move said jaws toward closed positions on swinging of said lever in said one direction.

References Cited in the file of this patent UNITED STATES PATENTS 2,514,130 Jones July 4, 1950 2,523,385 Mead Sept. 26, 1950 2,598,650 Smith et a1. May 27, 1952 2,783,797 Blatt et al., Mar. 5, 1957 

